Neutralizing inductive disturbances.



J. B. TAYLOR.

NEUTRALIZING INDUGTIV'E DISTURBANUEB. urmcnxox FILED nov. 20, 1967.

920,097, Patented Apr. 27, 1909.

wifinesses inventon 4% .44; John B.Tay!ori5 0; b ma UNITED STATES PATENT OFFICE.

AHh'ltjNUli 'lt) liltNltltal, liLllU'llllt' CUM- l" NEW YORK.

NEUTRA'LIZING INDUGTIVE DIBTURB ANCES Original application filed July 28, 1906, Serial No. 328,162. Divided and Specification of Letters Patent.

Patented April 27, 1909.

this application filed November 20, 1907.

Serial No, 403,013.

' ing is a specification.

This 18 a division of my application, Serial No. 328,162, filed July28, 1906.

In general, any conductor which is carrying current induces an electromotive force in neighboring conductors. This induced electromotiye force may or may not be considered a disturbance, depending on its magnitude and the use to which the conductor is put. Iii-the most common case where this disturbance becomes a serious matter, as in the case of telephone or telegraph lines which are exposed to alternating current transmission lines, the disturbance may be due to electromagnetic induction, depenclin on therelative locations of two circuits, and the current carried by the conductor,

In general, a balanced single-phase, or .iolyphasc,transmission line gives little troultle to neighboring conductors, and'by suitable transpositionsthe disturbance can be either entirely eliminated, or reduced to such a point that it isno longer a serious matter. As soon, however, as the transmission line becomes unbalanced (a line is balanced only so long as the algebraic sum of the currents in the condlurtors equals zero, and the algebraic'su n or the potentials also equals zero) it is impossible to neutralize the inductive action by transpositions.

The simplest and typical case of an unbalanced system, which may cause disturbance on telephone or telegraph lines, is the single-phase trolley. In this case a single conductor is connected to one terminal of an alternating--current generator; return circuit being formed through the earth, or what amounts to the same thing, through rails laid on the surface of the earth. In such a case'it is, obviously, impossible to transpose.

the. working conductor, or trolley with the rails, and while there may be certain positions in, vyhich a conductor (such as a telegraph line} would be squall afiected by cur- :rent intro ley and'reils, it ,s difiicult to find this position andimpracticable to suspend the telegraph or telephone lines at such a point.

The object of the present invention is'--to provide means for neutralizing the effect of electromagnetic induction in a s' naling conductor such as a telegraph or to ephone line locatcdin proximity to an alternating cur= rent transmission line.

It consists in means for producing an electroinotive force sufiicient t0 counterbalance that-induced in the signaling conductor.

The accompanying drawing is a diagram showing a mode of neutralizing the effect of electroma netic'induction.

In the figure there is shown an alternating current generator 1, which simply for the sake of illustration is represented as a single phase generator sup lying current to a transmission line 2, sue for instance as an overhead conductor conveying current to a trolley car 3. The return is through the earth or the rails 2'. unity to this line is a signaling conductor 4, such for example as a telegraph or tele phone wire. Under such circumstances, the electromotive force induced in the telegraph wire is proportional to the current in the trolley line and also to the distance through which thiscurrent flows. In order to counterbalance or; neutralize this inductive efiect, there is provided in the figure a current transformer whose primary 5'1scon-- nected; in series with the trolley line, while its secondary (i is closed upon itself through a resistance 7 One end of said resistance is connected with the telegraph wire, which is cut at this point. The other end of said wire is connected to a switch lever 8, by means of which more or less of the resistance can be cut intoseri'es with the telegraph wire, causing a greater or less pro ortion, respectively, 0 the electromotive orce induced in the secondary coil 6 to be thrown upon the telegraph Wire. y winding the secondary coil in the roper direction, this impressed electromotive force will counterbalance the electromotive forcev due to electroma. etic inductance. It will of course be on ers'tood that the/proper ratio must be selected between the primary and secondary coils 5, 6,. and the proper value given to the resistance in series with the telegraph wire. a

A single transformer might be suflicient in case the load were concentrated at a particular point. In the typical case of the railway, however, the load is continually changing its position, so that a single transformer will not serve. In such a case, a number of transformers should be inserted, preferably at equal distances, as indicated by the apparatus shown at 9. It is obvious that this construction 'will only approximately "neutralize the inductive action, but that exact neutralization will be more nearly realized in accordance with the increase in the number of transformers employed.

What I claim as new and desire to secure by Letters Patent of the United States, is,-

1. Means for. neutralizing electroma' netic inductive disturbances between p 'rallel aerial conductors, comprisin a transformer having one coil in series wit the conductor carrying the inducing current, the other coil being in circuit with the other conductor, and a resistance in circuit with said last named coil.

2. Means for neutralizing electromagnetic inductive disturbances between parallel aerial conductors,'comprising a transformer having one coil in serles with the inducing conductor, a resistance in closed circuit with the other coil, and having one end connected with one terminal of the other conductor,

and means for adjustably connecting the other terminal of said conductor with said resistance. a

In witness whereof, I have hereunto set my hand this 18th day of November, 1907.

4 JOHN B. TAYLOR. \Vitnesses:

BENJAMIN B.- HULL, HELEN Omonn. 

